Dishwashers are equipped with what is termed a water inlet or water inlet device via which the appliance is filled with fresh water, i.e. mains water.
A generic dishwasher has such a water inlet device, the housing of which is provided with an inlet opening to which a fresh water feed line is connected. On the outlet side the housing of the water inlet device opens via a first washing container opening into a washing chamber of a washing container of the dishwasher. During a wash cycle the washing container can be filled with fresh water via the water inlet device.
The water inlet device also has an expansion system which is assigned to the washing chamber. An expansion in the volume of air or water vapor enclosed in the washing chamber during the time it is being heated can be balanced out by way of the expansion system. For that purpose a so-called expansion line leads into the washing chamber. At the same time it must be ensured that if negative pressure occurs in the water feed line, e.g. due to corresponding flow conditions in a domestic water supply system, liquid cannot escape from the dishwasher into the domestic water supply system due to the suction effect of the negative pressure.